Is there a way to create a copy of the default keymap configuration?
Holy smokes, this was miserable to figure out but this appears to work:

        import bpy

        wm = bpy.context.window_manager
        CopiedMap = wm.keyconfigs.new("CopiedMap")

        #Get list of default keymap items
        keymaps = wm.keyconfigs.default.keymaps.items()
        for i in keymaps:

            #Put default values in to new keymaps 
            CopiedMap.keymaps.new(i[1].name, space_type= i[1].space_type, 
                                  region_type=i[1].region_type) 

            #Get list of default keymap_items contained 
            #within the keymap 
            keymap_items = i[1].keymap_items.items()
            for j in keymap_items:

                #Put values in to new keymap_items
                CopiedMap.keymaps[i[1].name].keymap_items.new(j[1].idname, j[1].type, j[1].value, any=j[1].any, 
                                                              shift=j[1].shift, ctrl=j[1].ctrl, alt=j[1].alt, 
                                                              oskey=j[1].oskey, key_modifier=j[1].key_modifier)


I'm not a very good scripter so this is probably not a very good answer, but maybe it'll get you by until somebody better at this comes along. :)